Power supply



FIG. 1 is a front elevational view of a power supply showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a front, top, right perspective view thereof.

The broken lines depict portions of the power supply that form no part of the claimed design. 

CLAIM The ornamental design for a power supply, as shown and described. 